Different tasks for processing crop material in an agricultural harvester require that a tensioned belt is guided over a deflecting roller and runs in a proper way. Well-known kinds of agricultural harvesters with belts guided over rollers are bale forming apparatuses (balers), combine harvesters, field choppers, and loader wagons.
A round baler forms round-cylindrical bales in a drum-shaped bale forming chamber. In one embodiment this bale forming chamber is surrounded by at least one endless elastic pressing belt and by several pressing rollers. The or every pressing belt is driven by at least one roller. The or every pressing belt is tensioned and is guided over several deflecting rollers. Loose crop material is injected into the bale forming chamber. The expanding loose material in the bale forming chamber applies pressure onto the or every pressing belt. The or every tensioned belt applies compressing pressure onto the loose material.
Further kinds of harvesters convey crop material towards and/or inside a chamber, e.g. a loading chamber or a threshing chamber or a pressing chamber. For conveying the crop material at least one conveyor belt is guided over at least one roller.
In particular in the case of a non-uniform distribution or non-uniform applied load of loose material in the bale forming chamber or further processing chamber the actual run of a pressing belt over a deflecting roller can deviate from a desired belt run. This deviation is undesired. Similar problems can occur in other kinds of harvesters. Several measures for auto-correcting an undesired belt run were proposed.
EP 1269827 B1 discloses a round baler (Rundballenpresse) with a pressing chamber (Pressraum CP). The circumferential surface of the pressing chamber CP is delimited by four parallel pressing belts (Pressriemen R1 bis R4), cf. FIG. 1 and par. [0021]. The four pressing belts R1 to R4 are deflected around several rollers, among them around the deflecting roller (Walze W). This roller W may be rotated in the direction of the arrow 3. It is required that the pressing belts R1 to R4 are guided such that the respective belt center axis is P1 to P4 (vorbestimmte Soll-Position). Four belt supports (Auflagen H1 bis H4) are mounted on the roller W in a sequence parallel to the roller axis and are positioned between the outer surface of the roller W and the inner surface of the respective pressing belt R1 to R4, cf. FIG. 1 and par. [0021]. The support H2 can be implemented as a shell or jacket (Hülse) made of plastic, rubber, or metal (Kunststoff, Gummi oder Metall). It is even possible to make the support H2 adjustable.
In one embodiment of EP 1269827 B1 the center axis of such a support H1 to H4 equals the desired position P1 to P4 of a pressing belt. In a variation the support H2 is not positioned symmetrically around the desired position P2 but is positioned with an offset x parallel to the roller axis, cf. FIG. 2 and par. [0023]. The task of both embodiments is to provide a self-centering effect (Selbstzentrierungseffekt) for the case that the pressing belt R2 is shifted laterally out of the desired position P2.
EP 0095688 B1 discloses a round baler which forms a round bale by means of eight parallel pressing belts 31 to 38, cf. FIG. 3. These pressing belts 31-38 are guided around a deflecting roller (Walze 22), cf. FIG. 4 and FIG. 5. The roller 22 comprises a kernel (Kern 91) made of steel and several rubber sleeves or jackets (Gummibüchsen) 93 to 100, one sleeve or jacket per pressing belt 31 to 38, cf. FIG. 5. A belt 31 to 38 has a larger width than a jacket 93 to 100.
EP 0950348 A1 discloses a round baler 10 with several pressing belts 24, 26, 28, 30 and several drive rollers 44, 48, 52, 56, cf. FIG. 2 and par. [0025]. Each belt 24, 26, 28, 30 is to be tracked in a controlled manner. FIG. 6 shows a driven roller 48with a sleeve 78 mounted over the circumferential surface of the roller 48. The sleeve 78 provides a crowning effect to the drive roller 48. The sleeve 78 is formed of a rubber material and provides an increased traction between the sleeve 78 made of rubber material and the inner surface of the belt 26. The drive roller 48 itself has a cylindrical surface made of steel. The sleeve 78 prevents belt slippage and improves tracking of the belt 26 by limiting its lateral or sideways moment. An improved tracking for centering of the weight belt is provided, cf. par. [0025]. In a further embodiment of EP 0950348 A1 a roller has a sleeve 78 and a helix structure 68 besides the sleeve, cf. FIG. 7 and par. [0026].
EP 2272320 B1 discloses a plurality of parallel belts 12 guided around a driven roller 10, cf. FIG. 1 and par. [0015]. FIG. 2 ff. show different embodiments of the claimed invention. The figures show the roller without the belts 12. A legging 14 (Belag, revêtement) is applied on the circumferential surface of the roller body, cf. FIG. 2. The legging 14 can be in the form of an elastomeric material, cf. par. [0015]. This material can be adhered to the roller body 16 or can be machined directly into the material of the roller body. The legging 14 is applied in discrete regions 20. In the embodiment of FIG. 2 ff. several grooves 24 in the roller surface form a herringbone pattern. In the embodiment of FIG. 7 several ribs 30 are arranged on the circumferential surfaces.
EP 2481691 A1 discloses a self-centering belt-roller arrangement. The deflecting roller is kept by two lateral lever arms which are positioned perpendicular to the roller rotating axis in two opposite directions.
U.S. Pat. No. 5,246,099 discloses a belt steering roller mechanism which actively corrects the run of an endless belt. FIG. 12 shows an endless belt 145 which is guided around two rollers 20 and 140. The drive roller 140 moves the belt 145 and the steering roller 20 is an idler roller. The steering roller 20 has a shaft 10, a rigid core 35 and an elastomer body 40, cf. FIG. 1, FIG. 2A and FIG. 2B. A plurality of longitudinally extending rigid members 45 are mounted in the elastomer body 40 near the outer diameter of the roller 20. These rigid members are separated by a plurality of longitudinal extending deformable sections 50. A flange plate 55 is located against the fore end 25 or against the aft end 30 and is held on the shaft 10 by a fastening means 60 such that the flange plate 55 can tilt, cf. FIG. 2B.
U.S. Pat. No. 3,075,633 discloses an automatic belt training roller assembly for a belt conveyor. FIG. 1 shows a cross-sectional view which shows a conveying reach 68 and a return reach 70 of a load carrying belt. A carrying roller assembly carries the conveying reach 68 and comprises a center primary load carrying roller 59 and a pair of wing rollers 60 and 61. The return reach 70 rests on a single roller 72 with a center portion of an increased diameter 78 with two ends 79 and 80.
U.S. Pat. No. 4,890,449 discloses a round baler 10 with an attachment 12 for guiding the pressing belts, cf. FIG. 1. The attachment 12 includes an elongated cylindrical roller 34 and a plurality of square plates 36 which are rigidly affixed to the roller 34 in an equally spaced relation along the longitudinal axis 40 of the roller 34. The metal plates 36 may be secured to the metal roller 34 by weldings 38, cf. FIG. 4. FIG. 2 shows a sequence of aid belts 24 guided over the roller 34 and separated by the plates 36.